It puts a strain on your muscles.
A: You're getting really toned these days.
B: I'm telling you it's these kick-boxing lessons I've been taking.
A: I heard the training is very rigorous.
B: It puts a strain on your muscles, but it's worth it.
이 운동은 근육을 긴장시켜요.
A: 너 요즘 점점 몸이 좋아지는 것 같아.
B: 있잖아, 킥복싱 레슨을 받고 있거든.
A: 훈련이 아주 힘들다고 들었는데.
B: 킥복싱은 근육을 긴장시키지만, 할 만한 운동이야.